Agreed, the boat should be dry when you pull that plug. No water should be making it's way in. Yeah, I do see how that rub rail seam could be a cause, splash, and the water goes up and down the hull into the foam. On my boat, that seam was super sealed up, which was good to see. This boat for sure just sat outside uncovered and in the rain, evidenced by all the color fade. The gelcoat lost it's clarity years ago. But I have tested a fix for that which seems to work. yay